Prognostic impact of discrepant Ki67 and mitotic index on hormone receptor-positive, HER2-negative breast carcinoma

Mitotic Index Analysis

Cellular division is a fundamental process of cellular growth. First, cells replicate their DNA in S phase and then undergo mitosis which, under normal conditions, leads to complete cell division. Moreover, mitotic activity correlates to cellular growth activity. The simplest and classical method to measure mitotic activity (mitotic index (MI)), is the manual counting of mitotic cells among a given cell population of interest. The latter can be accomplished via phase contrast microscope observation. However, Giemsa staining may improve accuracy and consistency. Fluorescence immunostaining targeting specific phosphorylations of proteins at critical cell cycle steps will provide further improved analysis via high-throughput capacity of flow or imaging cytometer. Finally, time lapse image analysis provides quantitative and qualitative metrics delineating the process of cellular division including timing of division, duration of mitosis, and failure to procced through or complete mitosis.

Artificial intelligence scale-invariant feature transform algorithm-based system to improve the calculation accuracy of Ki-67 index in invasive breast cancer: a multicenter retrospective study

BACKGROUND

Ki-67 is a key indicator of the proliferation activity of tumors. However, no standardized criterion has been established for Ki-67 index calculation. Scale-invariant feature transform (SIFT) algorithm can identify the robust invariant features to rotation, translation, scaling and linear intensity changes for matching and registration in computer vision. Thus, this study aimed to develop a SIFT-based computer-aided system for Ki-67 calculation in breast cancer.

METHODS

Hematoxylin and eosin (HE)-stained and Ki-67-stained slides were scanned and whole slide images (WSIs) were obtained. The regions of breast cancer (BC) tissues and non-BC tissues were labeled by experienced pathologists. All the labeled WSIs were randomly divided into the training set, verification set, and test set according to a fixed ratio of 7:2:1. The algorithm for identification of cancerous regions was developed by a ResNet network. The registration process between paired consecutive HE-stained WSIs and Ki-67-stained WSIs was based on a pyramid model using the feature matching method of SIFT. After registration, we counted the nuclear-stained Ki-67-positive cells in each identified invasive cancerous region using color deconvolution. To assess the accuracy, the AI-assisted result for each slice was compared with the manual diagnosis result of pathologists. If the difference of the two positive rate values is not greater than 10%, it was a consistent result; otherwise, it was an inconsistent result.

RESULTS

The accuracy of the AI-based algorithm in identifying breast cancer tissues in HE-stained slides was 93%, with an area under the curve (AUC) of 0.98. After registration, we succeeded in identifying Ki-67-positive cells among cancerous cells across the entire WSIs and calculated the Ki-67 index, with an accuracy rate of 91.5%, compared to the gold standard pathological reports. Using this system, it took about 1 hour to complete the evaluation of all the tested 771 pairs of HE- and Ki-67-stained slides. Each Ki-67 result took less than 2 seconds.

CONCLUSIONS

Using a pyramid model and the SIFT feature matching method, we developed an AI-based automatic cancer identification and Ki-67 index calculation system, which could improve the accuracy of Ki-67 index calculation and make the data repeatable among different hospitals and centers.

A new pathological assessment method to assess residual lesions after neoadjuvant chemotherapy for breast cancer, residual disease in breast and nodes combined with Ki-67 (RDBN-K)

Background

The accurate assessment of residual tumor tissue after neoadjuvant chemotherapy (NAC) for breast cancer is closely related to the subsequent treatment and prognosis of patients. The objective of this study is to develop a new pathological assessment metric for breast cancer patients through combining residual disease in breast and nodes (RDBN) and the Ki-67 expression status after NAC. We call the new metric residual disease in breast and nodes combined with Ki-67 (RDBN-K) and aim to study its significance for prognosis.

Methods

A total of 723 breast cancer patients with TNM staging II to III who received NAC and surgical treatment underwent residual disease evaluation by RDBN-K and RDBN. All patients were followed up for a median of 44 months. We used pairwise stratified analysis to compare the accuracy and clinical significance of the RDBN and RDBN-K.

Results

Pairwise stratified analysis revealed that DFS and OS had larger difference between RDBN-K-3 and RDBN-K-4 compared to between RDBN-3 and RDBN-4. Moreover, RDBN-K also showed larger differences in OS between stage 2 and 3 compared to RDBN alone.

Conclusions

Incorporating Ki-67 expression status into RDBN improved the accuracy in residual tumor burden assessment after NAC. RDBN-K is a better metric for predicting treatment outcomes and identify patients who warrant follow-up intensive treatment.

The long non-coding RNA SAMMSON is essential for uveal melanoma cell survival

Long non-coding RNAs (lncRNAs) can exhibit cell-type and cancer-type specific expression profiles, making them highly attractive as therapeutic targets. Pan-cancer RNA sequencing data revealed broad expression of the SAMMSON lncRNA in uveal melanoma (UM), the most common primary intraocular malignancy in adults. Currently, there are no effective treatments for UM patients with metastatic disease, resulting in a median survival time of 6-12 months. We aimed to investigate the therapeutic potential of SAMMSON inhibition in UM. Antisense oligonucleotide (ASO)-mediated SAMMSON inhibition impaired the growth and viability of a genetically diverse panel of uveal melanoma cell lines. These effects were accompanied by an induction of apoptosis and were recapitulated in two uveal melanoma patient derived xenograft (PDX) models through subcutaneous ASO delivery. SAMMSON pulldown revealed several candidate interaction partners, including various proteins involved in mitochondrial translation. Consequently, inhibition of SAMMSON impaired global, mitochondrial and cytosolic protein translation levels and mitochondrial function in uveal melanoma cells. The present study demonstrates that SAMMSON expression is essential for uveal melanoma cell survival. ASO-mediated silencing of SAMMSON may provide an effective treatment strategy to treat primary and metastatic uveal melanoma patients.

Assessment of proliferation in breast cancer: cell cycle or mitosis? An observational study

BACKGROUND AND AIMS

Proliferation is an important indicator of breast cancer (BC) prognosis, but is assessed using different approaches. Not all cells in the cell cycle are committed to division. This study aimed to characterise quantitative differences between BC cells in the cell cycle and those in mitosis and assess their relationship with other pathological parameters.

METHODS AND RESULTS

A cohort of BC sections (n = 621) was stained with haematoxylin and eosin and immunohistochemistry for Ki-67. The proportion of mitotic cells and Ki-67-positive cells was assessed in the same areas. The Cancer Genome Atlas (TCGA) BC cohort was used to assess MKI-67 transcriptome level and its association with the mitotic counts. The mean proportion of BC cells in the cell cycle was 24% (range = 1-90%), while the mean proportion of BC cells in mitosis was 5% (range = 0-73%). A low proportion of mitoses to whole cycling cells was associated with low histological grade tumours and the luminal A molecular subtype, while tumours with a high proportion of mitoses to the overall cycling cells were associated with triple-negative subtype, larger tumour size, grade 3 tumours and lymph node metastasis. The high mitosis/low Ki-67-positive cells tumours showed a significant association with variables of poor prognosis, including high-grade and triple-negative subtypes.

CONCLUSION

The proportion of BC cells in the cell cycle and mitosis is variable. We show that not only the number of cells in the cell cycle or mitosis, but also the difference between them, provides valuable information on tumour aggressiveness.

Adipose-derived stem/stromal cell secretome modulates breast cancer cell proliferation and differentiation state towards aggressiveness

It is becoming increasingly evident that mesenchymal stem/stromal cells are recruited by cancer cells from nearby endogenous host stroma and promote events such as tumor proliferation, angiogenesis, invasion, and metastasis, as well as mediate therapeutic resistance. Consequently, understanding the regulatory mechanisms of ASCs that influence the tumor microenvironment may provide an avenue for further treatment. To understand the role of the ASC secretome in breast cancer cell proliferation, death, and phenotype alteration, adipose-derived stem cell-conditioned medium (mASC) was used to cultivate MCF-7 and MDA-MB-231 cells. These breast cancer cells in mASC showed a shorter doubling time, higher frequency of EdU positivity, and higher levels of phosphorylated histone 3. In addition, increased expression of cyclin B1 was observed, suggesting that proliferation was induced. The mASC was also able to increase apoptosis in MCF-7 cells, which was confirmed by caspase-7 activation. The number of tumor-initiating cells (CD44⁺ CD24^-/low) and migration capacity were increased in cells cultivated in mASC. These data collectively suggest that ASC-conditioned medium can induce selective pressure by increasing cell proliferation, giving rise to a more aggressive phenotype in MCF-7 and MDA-MB-231 cells. Our study provides a foundation for further elucidation of the precise mechanism underlying ASCs in breast cancer cells and the modulation of ASCs in potential therapeutic uses.

Nodal status in luminal A invasive breast cancer: relationships with cytotoxic CD8 + and regulatory FOXP3 + cells tumor-associated infiltrate and other prognostic factors

Luminal A breast cancers are generally associated with low metastatic potential and good prognosis. However, there is a proportion of patients, who present with metastases in lymph nodes. The aim of our study was to determine the association between the number of positive lymph nodes and infiltrates of tumor-associated cytotoxic CD8 + (CTLs), regulatory FOXP3 + T cells (Tregs), as well as other prognostic factors. Immunohistochemistry (IHC) for CD8 + and FOXP3 + was performed in 87 formalin-fixed paraffin-embedded primary breast cancer tissues, and cell infiltrate was assessed under light microscope. We observed that node-positive cases were associated with higher numbers of Treg cells and lower CTL/Treg ratio. There was also an inverse correlation between the CTL/Treg ratio and the number of metastatic lymph nodes. Similar relationships were found between the number of metastatic lymph nodes and Treg density or CTL/Treg ratio in pT1 BC. An elevated intratumoral CTL/Treg ratio was associated with pN0 stage. The relationship between lymphovascular invasion (LVI) and Treg density was also noted in node-negative tumors. In addition, more advanced nodal stage was related to LVI, higher pT, and lower PR expression. The numbers of CD8 + and FOXP3 + were also associated with tumor size, histologic grade, PR expression, and mitotic index. The results of our study suggested that the levels of tumor-infiltrating regulatory and cytotoxic cells as well as the balance between them play a role in lymphovascular spread of luminal A breast cancers.

Unravelling actionable biology using transcriptomic data to integrate mitotic index and Ki-67 in the management of lung neuroendocrine tumors

Pulmonary neuroendocrine tumors (NETs) are a heterogeneous family of malignancies whose classification relies on morphology and mitotic rate, unlike extrapulmonary neuroendocrine tumors that require both mitotic rate and Ki-67. As mitotic count is proportional to Ki-67, it is crucial to understand if Ki-67 can complement the existing diagnostic guidelines, as well as discover the benefit of these two markers to unravel the biological heterogeneity. In this study, we investigated the association of mitotic rate and Ki-67 at gene- and pathway-level using transcriptomic data in lung NET malignancies. Lung resection tumor specimens obtained from 28 patients diagnosed with NETs were selected. Mitotic rate, Ki-67 and transcriptomic data were obtained for all samples. The concordance between mitotic rate and Ki-67 was evaluated at gene-level and pathway-level using gene expression data. Our analysis revealed a strong association between mitotic rate and Ki-67 across all samples and cell cycle genes were found to be differentially ranked between them. Pathway analysis indicated that a greater number of pathways overlapped between these markers. Analyses based on lung NET subtypes revealed that mitotic rate in carcinoids and Ki-67 in large cell neuroendocrine carcinomas provided comprehensive characterization of pathways among these malignancies. Among the two subtypes, we found distinct leading-edge gene sets that drive the enrichment signal of commonly enriched pathways between mitotic index and Ki-67. Overall, our findings delineated the degree of benefit of the two proliferation markers, and offers new layer to predict the biological behavior and identify high-risk patients using a more comprehensive diagnostic workup.

Lactate concentration in breast cancer using advanced magnetic resonance spectroscopy

BACKGROUND

Precision medicine in breast cancer demands markers sensitive to early treatment response. Aerobic glycolysis (AG) upregulates lactate dehydrogenase A (LDH-A) with elevated lactate production; however, existing approaches for lactate quantification are either invasive or impractical clinically.

METHODS

Thirty female patients (age 39-78 years, 15 grade II and 15 grade III) with invasive ductal carcinoma were enrolled. Lactate concentration was quantified from freshly excised whole tumours with double quantum filtered (DQF) magnetic resonance spectroscopy (MRS), and Nottingham Prognostic Index (NPI), LDH-A and proliferative marker Ki-67 were assessed histologically.

RESULTS

There was a significantly higher lactate concentration (t = 2.2224, p = 0.0349) in grade III (7.7 ± 2.9 mM) than in grade II (5.5 ± 2.4 mM). Lactate concentration was correlated with NPI (ρ = 0.3618, p = 0.0495), but not with Ki-67 (ρ = 0.3041, p = 0.1023) or tumour size (r = 0.1716, p = 0.3645). Lactate concentration was negatively correlated with LDH-A (ρ = -0.3734, p = 0.0421).

CONCLUSION

Our results showed that lactate concentration in whole breast tumour from DQF MRS is sensitive to tumour grades and patient prognosis.

Association between Ki-67 expression and clinicopathological features in prognosis of breast cancer: A retrospective cohort study

Background:

Breast cancer is the most common diagnosed female cancer. Breast cancer is also the leading cause of cancer death in females accounting for 13.7% of female cancer-related mortality globally. Variable known prognostic factors such as histological tumor type, tumor size, nodal status, grade, age, and estrogen receptor (ER) status and the proliferation marker – Ki-67 influence the type of treatment decision. The purpose of this present study is to investigate the association between Ki-67 expression with several clinicopathological variables and patients’ outcome.

Materials and Methods:

This is a retrospective cohort study from September 2008 to March 2017; 165 newly diagnosed breast cancer patients were enrolled in the study. Ki67 levels were measured using immunohistochemistry and compared with clinicopathological variables. The relation of Ki67 expression with disease-free survival (DFS) and overall survival (OS) was also analyzed.

Results:

The result of this study revealed that age, tumor size, menopausal status, and human epidermal growth factor receptor 2 (HER2) status had no effect on the patients’ outcome. Patients with ER-positive, progesterone receptor (PR)-positive, and HER2-negative tumors expressed a higher rate of Ki-67 (>10%) than patients with ER-negative, PR-negative, and HER2-positive tumors, respectively. However, we found that Ki-67 levels were not significantly increased statistically with ER, PR, and HER2 statuses. There was a statistically significant correlation between Ki-67 expression and with higher stages of the disease. Multivariate analysis showed that Ki-67 expression could not to be an independent prognostic factor for 5-year OS and DFS. Furthermore, p53 status was only prognostic factor for 5-year OS whereas higher stages of disease and p53 status were prognostic factors for 5-year DFS.

Conclusion:

Ki67 could not be an independent variable for prediction of breast cancer outcome.

Impact of Topoisomerase IIα, PTEN, ABCC1/MRP1, and KI67 on triple-negative breast cancer patients treated with neoadjuvant chemotherapy

PURPOSE

Triple-negative breast cancer (TNBC) patients with residual disease following neoadjuvant chemotherapy (NAC) harbor higher risk of relapse, and eventual demise compared to those who achieve pathologic complete response. Therefore, in this study, we assessed a panel of molecules involved in key pathways of drug resistance and tumor progression before and after NAC in TNBC patients, in order to clarify the underlying mechanisms.

METHODS

We studied 148 TNBC Japanese patients treated with anthracycline/taxane-based NAC. KI67, Topoisomerase IIα (TopoIIα), PTEN, p53, Bcl2, vimentin, ABCG2/BCRP1, ABCB1/MDR1, and ABCC1/MRP1 were immunolocalized in surgical pathology materials before and after NAC.

RESULTS

The status of vimentin and increasing labeling index (LI) of TopoIIα and KI67 in biopsy specimens were significantly associated with those who responded to NAC treatment. The abundance of p53 (p = 0.003), ABCC1/MRP1 (p = 0.033), ABCB1/MDR1 (p = 0.022), and a loss of PTEN (p < 0.0001) in surgery specimens following treatment were associated with pathologic parameters. TopoIIα, PTEN, and ABCC1/MRP1 status predicted pathologic response. In addition, the status of PTEN, ABCC1/MRP1, ABCB1/MDR1, Bcl2, and vimentin in surgical specimens was also significantly associated with adverse clinicopathological factors in surgery specimens, suggesting that these alterations could be responsible for tumor relapse in TNBC patients.

CONCLUSION

KI67, TopoIIα, PTEN, and ABCC1/MRP1 status could predict treatment response and/or eventual clinical outcomes. These results could also provide an insight into the mechanisms of drug resistance and relapse of TNBC patients receiving NAC.

Critical review of axillary recurrence in early breast cancer

Around 2% of early breast cancer cases treated with axillary lymph node dissection (ALND) underwent axillary recurrence (AR) and it has a deleterious effect in prognosis. Different scenarios have incorporated Sentinel Lymph Node (SLN) Biopsy (SLNB) instead of ALND as part of the standard treatment and more effective systemic treatment has also been incorporated in routine management after first curative surgery and after regional recurrence. However, there is concern about the effect of SLNB alone over AR risk and how to predict and treat AR. SLN biopsy (SLNB) has been largely accepted as a valid option for SLN-negative cases, and recent prospective studies have demonstrated that it is also safe for some SLN-positive cases and both scenarios carry low AR rates. Different studies have identified clinicopathological factors related to aggressiveness as well as high-risk molecular signatures can predict the development of locoregional recurrence. Other publications have evaluated factors affecting prognosis after AR and find that time between initial treatment and AR as well as tumor aggressive behavior influence patient survival. Retrospective and prospective studies indicate that treatment of AR should include local and systemic treatment for a limited time.

Improving the Subcutaneous Mouse Tumor Model by Effective Manipulation of Magnetic Nanoparticles-Treated Implanted Cancer Cells

Murine tumor models have played a fundamental role in the development of novel therapeutic interventions and are currently widely used in translational research. Specifically, strategies that aim at reducing inter-animal variability of tumor size in transplantable mouse tumor models are of particular importance. In our approach, we used magnetic nanoparticles to label and manipulate colon cancer cells for the improvement of the standard syngeneic subcutaneous mouse tumor model. Following subcutaneous injection on the scruff of the neck, magnetically-tagged implanted cancer cells were manipulated by applying an external magnetic field towards localized tumor formation. Our data provide evidence that this approach can facilitate the formation of localized tumors of similar shape, reducing thereby the tumor size's variability. For validating the proof-of-principle, a low-dose of 5-FU was administered in small animal groups as a representative anticancer therapy. Under these experimental conditions, the 5-FU-induced tumor growth inhibition was statistically significant only after the implementation of the proposed method. The presented approach is a promising strategy for studying accurately therapeutic interventions in subcutaneous experimental solid tumor models allowing for the detection of statistically significant differences between smaller experimental groups.

IMP3 as a prognostic biomarker in patients with malignant peritoneal mesothelioma

Malignant peritoneal mesothelioma (MPeM) is an incurable cancer with poor prognosis, and several biomarkers have been suggested for screening of MPeM. The aim of our study was to evaluate the prognostic significances of IMP3 and Fli-1 in MPeM. Diagnostic biopsies of 44 MPeM patients were centrally collected and were immunohistochemically analyzed for expression of IMP3, Fli-1, and Ki-67. Labeling was assessed by 2 pathologists. Complete clinical information and follow-up were obtained from patients' records. Carcinomas expressed Fli-1 in 42 (95.5%) of 44 specimens, and IMP3 in 23 (52.3%) of 44 specimens. Spearman ρ analysis revealed that Fli-1 expression was related to both histologic type and Ki-67 labeling index (Ki-67LI; r = -0.500, P < .05; r = 0.358, P < .05), and IMP3 expression was related to Ki-67LI (r = 0.401, P < .05). A Kaplan-Meier analysis and univariate Cox regression analysis showed that tumor-directed treatment, a lower peritoneal carcinomatosis index, stage I, lower Ki-67LI, and lower level of IMP3 expression had a statistically significantly positive effect on overall survival; Fli-1 did not affect overall survival in the univariate analysis (hazard ratio [HR], 1.026; P = .904). A Kaplan-Meier analysis showed the correlation between IMP3-Fli-1 and overall survival, whereas univariate and multivariate Cox regression analyses did not confirm the correlation. Cox regression analysis revealed that IMP3 expression (HR, 2.311 [95% confidence interval, 1.190-4.486]; P = .013) and no tumor-directed treatment (HR, 0.189 [95% confidence interval, 0.086-0.416]; P = .000) retained independent prognostic significance, both with negative effect on OS. IMP3, along with tumor-directed treatment protocols, is a powerful prognosticator in patients with MPeM.

Ki67 Changes Identify Worse Outcomes in Residual Breast Cancer Tumors After Neoadjuvant Chemotherapy

BACKGROUND

Several breast cancer (BC) trials have adopted pathological complete response (pCR) as a surrogate marker of long-term treatment efficacy. In patients with luminal subtype, pCR seems less important for outcome prediction. BC is a heterogeneous disease, which is evident in residual tumors after neoadjuvant-chemotherapy (NAC). This study evaluates changes in Ki67 in relation to disease-free survival (DFS) and overall survival (OS) in patients without pCR.

SUBJECTS, MATERIALS, AND METHODS

Four hundred thirty-five patients with stage IIA-IIIC BC without pCR after standard NAC with anthracycline and paclitaxel were analyzed. We analyzed the decrease or lack of decrease in the percentage of Ki67-positive cells between core biopsy samples and surgical specimens and correlated this value with outcome.

RESULTS

Twenty-five percent of patients presented with luminal A-like tumors, 45% had luminal B-like tumors, 14% had triple-negative BC, 5% had HER2-positive BC, and 11% had triple-positive BC. Patients were predominantly diagnosed with stage III disease (52%) and high-grade tumors (46%). Median Ki67 level was 20% before NAC, which decreased to a median of 10% after NAC. Fifty-seven percent of patients had a decrease in Ki67 percentage. Ki67 decrease significantly correlated with better DFS and OS compared with no decrease, particularly in the luminal B subgroup. Multivariate analysis showed that nonreduction of Ki67 significantly increased the hazard ratio of recurrence and death by 3.39 (95% confidence interval [CI] 1.8-6.37) and 7.03 (95% CI 2.6-18.7), respectively.

CONCLUSION

Patients without a decrease in Ki67 in residual tumors after NAC have poor prognosis. This warrants the introduction of new therapeutic strategies in this setting.

IMPLICATIONS FOR PRACTICE

This study evaluates the change in Ki67 percentage before and after neoadjuvant chemotherapy (NAC) and its relationship with survival outcomes in patients with breast cancer who did not achieve complete pathological response (pCR). These patients, a heterogeneous group with diverse prognoses that cannot be treated using a single algorithm, pose a challenge to clinicians. This study identified a subgroup of these patients with a poor prognosis, those with luminal B-like tumors without a Ki67 decrease after NAC, thus justifying the introduction of new therapeutic strategies for patients who already present a favorable prognosis (luminal B-like with Ki67 decrease).

Using computer assisted image analysis to determine the optimal Ki67 threshold for predicting outcome of invasive breast cancer

Background

Ki67 positivity in invasive breast cancers has an inverse correlation with survival outcomes and serves as an immunohistochemical surrogate for molecular subtyping of breast cancer, particularly ER positive breast cancer. The optimal threshold of Ki67 in both settings, however, remains elusive. We use computer assisted image analysis (CAIA) to determine the optimal threshold for Ki67 in predicting survival outcomes and differentiating luminal B from luminal A breast cancers.

Methods

Quantitative scoring of Ki67 on tissue microarray (TMA) sections of 440 invasive breast cancers was performed using Aperio ePathology ImmunoHistochemistry Nuclear Image Analysis algorithm, with TMA slides digitally scanned via Aperio ScanScope XT System.

Results

On multivariate analysis, tumours with Ki67 ≥14% had an increased likelihood of recurrence (HR 1.941, p=0.021) and shorter overall survival (HR 2.201, p=0.016). Similar findings were observed in the subset of 343 ER positive breast cancers (HR 2.409, p=0.012 and HR 2.787, p=0.012 respectively). The value of Ki67 associated with ER+HER2-PR<20% tumours (Luminal B subtype) was found to be <17%.

Conclusion

Using CAIA, we found optimal thresholds for Ki67 that predict a poorer prognosis and an association with the Luminal B subtype of breast cancer. Further investigation and validation of these thresholds are recommended.

Knockout validation of antibodies to Ki67: a marker for cellular proliferation

At Abcam, providing a high level of validation has always been a priority and our strategies are constantly evolving as new technologies are developed. The recent knockout (KO) validation initiative, made possible through a partnership with Horizon Discovery and the use of their CRISPR/Cas9 KO cell lines, addresses both antibody specificity and reproducibility on a large scale.

Ki67 is a proliferation marker and determining its expression levels has prognostic and predictive values in cancer (1–5). Hence, it is critical that antibodies used to target Ki67 are highly specific. This study demonstrates the evolving strategies used in our laboratory to validate antibodies to Ki67. The use of a human haploid cell lines where Ki67 expression has been knocked out has unequivocally identified antibodies that bind specifically to Ki67.

Utilising this technology has enabled KO validation of antibodies and, at the time of abstract submission, there are over 650 KO validated antibodies on our catalogue. It is our hope that by using this technique we can help to raise industry standards and contribute to the generation of reproducible research.

Ki67 Frequency in Breast Cancers without Axillary Lymph Node Involvement and its Relation with Disease-free Survival

BACKGROUND

Breast cancer prognosis is influenced by several histopathology and clinical factors including expression of Ki67 which may have a predictive role in lymph node negative breast cancer patients. The aim of this study was to assess Ki67 expression in breast cancers without axillary lymph node involvement and to evaluate its prognostic value with regard to disease-free survival.

MATERIALS AND METHODS

Subjects were selected from non-metastatic invasive breast cancer patients who were referred to the oncology department of Ghaem hospital during 1 April 2001 to 1 April 2008. Ki67 levels were measured using immunohistochemistry (IHC) and compared with clinicopathological features. The relation of Ki67 expression with disease-free survival was also analysed.

RESULTS

A total of 106 women with a mean age of 49 were examined. Some 94.3% were classified as having invasive ductal carcinomas and the mean tumour diameter at the time of diagnosis was 2.8 cm. Some 50.9% of cases were ER positive and 47.2% were PR positive. P53 expression was positive in 48.1% of the cases. According to the IHC results, only 8.5% of the patients were Her2/neu positive. Ki67 was positive in 66 (62.3%) with a significant relation to lower age (p=0.0229) and P53 positivity (p=0.005). After an average of 40-months follow up, 13 (12.3%) demonstrated recurrence, most commonly systemic. Of 13 cases with relapse, 10 patients (77%) were Ki67 positive.

CONCLUSIONS

In our population Ki67 appeared to be an independent prognostic factor for three-year survival. However, we stress that a survival study with a bigger sample size would help to support this conclusion.

Breastfeeding and Immunohistochemical Expression of ki-67, p53 and BCL2 in Infiltrating Lobular Breast Carcinoma

Background/Aim

Invasive lobular breast carcinoma is the second most common type of breast cancer after invasive ductal carcinoma. According to the American Cancer Society, more than 180,000 women in the United States find out they have invasive breast cancer each year. Personal history of breast cancer and certain changes in the breast are correlated with an increased breast cancer risk. The aim of this work was to analyze breastfeeding in patients with infiltrating lobular breast carcinoma, in relation with: 1) clinicopathological parameters, 2) hormonal receptors and 3) tissue-based tumor markers

Materials and Methods

The study included 80 women with ILC, 46 of which had breastfeed their children. Analyzed parameters were: age, tumor size, axillary lymph node (N), distant metastasis (M), histological grade (HG), estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), Ki-67, p53 and BCL2

Results

ILC of non-lactating women showed a larger (p = 0.009), lymph node involvement (p = 0.051) and distant metastasis (p = 0.060). They were also more proliferative tumors measured by Ki-67 (p = 0.053). Breastfeeding history did not influence the subsequent behavior of the tumor regardless of histological subtype

Conclusion

Lactation seems to influence the biological characteristics of ILC defining a subgroup with more tumor size, axillary lymph node involvement, distant metastasis and higher proliferation measured by ki-67 expression.